Complaints by Netflix and Internet backbone providers about network traffic congestion point to a real problem, with congestion on some networks lasting 18 hours a day, but the problems are sporadic and often temporary, according to preliminary results from a traffic study.

Traffic congestion at interconnection points between broadband providers and backbone providers doesn’t appear to be widespread, with congestion often just two or three hours a day, said David Clark, a senior research scientist at the Massachusetts Institute of Technology’s Computer Science and Artificial Intelligence Laboratory and one of the researchers investigating congestion complaints.

But in some cases, U.S. ISPs have experienced periods of congestion on interconnection points with backbone providers that last for months at a time, Clark said Wednesday. Still, many of the problems of congestion seem to point to disagreements over business arrangements related to mismatches between network capacity and demand, he said during a congressional briefing on traffic congestion.

In recent months, Netflix and backbone providers Cogent and Level 3 have accused U.S. broadband providers of purposefully allowing congestion into their networks as a way to charge Internet video services for carrying their traffic. Last week, U.S. Federal Communications Commission Chairman Tom Wheeler said his agency is looking into the complaints.

The ongoing congestion study, by MIT and the Cooperative Association for Internet Data Analysis at the University of California’s San Diego (UCSD) Supercomputer Center, is preliminary and doesn’t assign fault for congestion, but it does point to a poor experience for ISP customers and Netflix, said Clark, involved in the development of the Internet since the 1970s.

Clark didn’t call for new FCC regulations, but he said the agency’s attention is warranted. “It may be appropriate for the FCC to clear its throat and say, ‘what’s going on here?’” he said. In some cases, “this has been going on for months.”

Representatives of Netflix and the cable broadband industry both said the study supports their positions on who’s to blame for the congestion.

The study’s results are consistent with ISPs’ position that Netflix has routed its traffic through congested interconnection points in order to increase its bargaining power for traffic carriage by ISPs, said Ike Elliot, senior vice president of strategy for CableLabs, a research organization funded by cable broadband providers.

Streaming video providers are “not the victims of manipulated traffic congestion,” Elliot said. Instead they have chosen to sent traffic over congested routes “when they had many other options available,” he said.

But the study’s point that the congestion appears to be the result of business disagreements suggests traffic manipulation, said Ken Florence, vice president of content delivery at Netflix. Traffic graphs showing Netflix congestion on Comcast’s network suddenly disappeared when the two company signed a traffic agreement points to Netflix’s position that the congestion is “financial, not technical,” he said.

While both sides in the debate have an interest in maximizing their profits, the FCC has a role to play in protecting consumers, said Gene Kimmelman, president and CEO of digital rights group Public Knowledge.

The traffic management “can be constantly changed—or manipulated, if you want to call it that—for good business reasons or for maybe a more nefarious exercise of market power, so it calls out for policy oversight,” Kimmelman said.

Jeff Eisenach, a visiting scholar at free-market think tank the American Enterprise Institute, suggested a limited need for regulation. If companies on either side of the debate are manipulating traffic unfairly, antitrust agencies have the power to investigate, he said.

MIT and UCSD are looking for ways to collect more data, but in the meantime, streaming video providers and ISPs should look for ways to fix problems of congestion, Clark recommended. Clark said he doubts that ISPs like Comcast want their customers to have a bad experience watching Netflix.

ISPs have huge market power compared to Web content producers, Kimmelman countered. Cable broadband providers may not “want their customers to be unhappy, it just happens to be the case that most of them are,” he said. “How can that be the case?”

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